Positron Emission Tomography (hereinafter referred to as PET for short) is a non-invasive imaging method which can non-invasively, quantitatively and dynamically assess the metabolism, biochemical reactions, functional activities and perfusion of various organs of human body. Therefore, PET is used for early diagnosis and analysis of tumors, cardiac diseases and neurological diseases and plays a unique role in the prevention and treatment of serious diseases. During a PET imaging, it is needed to inject a drug marked with radioisotopes into a human body, an animal or an organism under detection. In the tissue of the object under detection, these radioisotopes encounter electrons and annihilate to generate a pair of γ photons. A detector at the periphery of the object under detection receives the γ photons and converts them into electrical signals. A series of processes are performed on these electrical signals, and an activity distribution of the object under detection is obtained by image reconstruction.
PET imager mainly includes a detector block, an electronics module and an image reconstruction module. The detector block receives and deposits γ photons and converts the γ photons into electrical signals; the electronics module processes and transmits these electrical signals; the image reconstruction module processes the signal obtained by the system to obtain an image of activity distribution of the object under detection.
The existing PETs are designed in a universal mode and pursue the improvement of overall performance in the field of view, all detector blocks have almost identical performance, besides, same configuration and layout are used for all objects under detection. However, in most cases, imaging with relatively high quality is only required for a certain region of interest. If the whole PET detection system is updated or upgraded to meet performance requirement with respect to a certain region of interest, there will be wasted and spare capacities in other regions. Furthermore, being constrained by the cost, it is impossible for the PET constructed in this way to use only detector blocks with extremely high performance, therefore extremely high imaging quality can not be obtained.
Therefore, in view of the technical problems, it is necessary to provide a PET detection structure and system with improved structure and application adaptability to overcome foregoing shortcomings.